the form letters were sent to president obama, senator roger wicker of mississippi, and mississippi judge sadie holland, who opened hers. >> a white kind of like grainy-type substance loose in the envelope. >> reporter: prosecutors say the missing pieces in the letters could refer to curtis' obsession with the sale of black market body parts. he's even written a book and tweeted about it. >> reporter: in a statement, his brother said, "we have no reason to believe kevin would be involved. we love him, and look forward to getting answers to make sense of all this." we met his neighbor lacey ross today. what do you think about the fact that he might have been cooking up ricin right next door? >> terrifying. really scary. i have two daughters. just knowing it could be that close to my children. >> reporter: just moments ago, members of the hazmat team arrived. a breached the door. took down the security camera. a lot of men are heavily armed, starting to gather evidence. the big question, what are they going to find inside? >> on the scene, thank you, matt gutman. >>> and coming up next here